Paper products and methods and systems for manufacturing such products

Abstract

Methods of producing cellulosic or lignocellulosic materials for use in papermaking include treating a cellulosic or lignocellulosic dry feedstock having a first average molecular weight with ionizing radiation, and controlling the dose of ionizing radiation such that the average molecular weight of the feedstock is reduced to a predetermined level. A method of producing an irradiated paper product includes treating a paper product including a first carbohydrate-containing material having a first molecular weight with ionizing radiation, and controlling the dose of ionizing radiation so as to provide an irradiated paper product with a second carbohydrate-containing material having a second molecular weight higher than the first molecular weight. Pulp and paper products are produced.

What is claimed is: 
     
       1. A method comprising:
 making a paper product on a papermaking machine, using a pulp produced by a process comprising treating a lignocellulosic dry feedstock having a first average molecular weight with at least 2.5 MRad of ionizing radiation to reduce the average molecular weight of the feedstock and pulping the treated lignocellulosic feedstock. 
 
     
     
       2. The method of  claim 1  further comprising subjecting the treated feedstock to a mechanical disintegrating process. 
     
     
       3. The method of  claim 1  further comprising applying acoustic energy to the treated feedstock. 
     
     
       4. The method of  claim 1  wherein the feedstock comprises wood chips. 
     
     
       5. The method of  claim 1  wherein the dose of ionizing radiation is from about 2.5 to about 100 MRad. 
     
     
       6. The method of  claim 1  wherein treating comprises irradiating with gamma radiation. 
     
     
       7. The method of  claim 1  wherein treating comprises irradiating with electron beam radiation. 
     
     
       8. The method of  claim 7  wherein electrons in the electron beam have an energy of at least 0.25 MeV. 
     
     
       9. The method of  claim 1  wherein the molecular weight is reduced to about 20,000 to 500,000. 
     
     
       10. The method of  claim 9  wherein the feedstock has a starting molecular weight of 1 million or greater. 
     
     
       11. The method of  claim 1  wherein the dose of ionizing radiation is from about 25 MRad to about 500 MRad.